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Olfactory receptors (OR), expressed on olfactory neurons, mediate the sense of smell. Recently, OR have also been shown to be expressed in non-olfactory tissues, including cells of the immune system. An analysis of single-cell transcriptomes of splenocytes of the gray short-tailed opossum (Monodelphis domestica) found OR are expressed on a subset of T cells, the γμ T cells, that are unique to marsupials and monotremes. A majority of opossum γμ T cells transcriptomes contain OR family 14 transcripts, specifically, from the OR14C subfamily. Amongst the mammals, the OR14 gene family is expanded in the genomes of marsupials and monotremes, and rarer or absent in placental mammals. In summary, here we demonstrate the intriguing correlation that a family of OR genes, abundant in the genomes of marsupials and monotremes, are ectopically expressed in a particular subset of T cells unique to the marsupials and monotremes.
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Comparative genomics of the T cell receptor μ locus in marsupials and monotremes
T cells are a primary component of the vertebrate adaptive immune system. There are three mammalian T cell lineages based on their T cell receptors (TCR). The αβ T cells and γδ T cells are ancient and found broadly in vertebrates. The more recently discovered γμ T cells are uniquely mammalian and only found in marsupials and monotremes. In this study, we compare the TCRμ locus (TRM) across the genomes of two marsupials, the grey short-tailed opossum and Tasmanian devil, and one monotreme, the platypus. These analyses revealed lineage specific duplications, common to all non-eutherian mammals described. There is conserved synteny in the TRM loci of both marsupials but not in the monotreme. Our results are consistent with an ancestral cluster organization which was present in the last common mammalian ancestor which underwent lineage specific duplications and divergence among the non-eutherian mammals.
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- Award ID(s):
- 2103367
- PAR ID:
- 10521561
- Publisher / Repository:
- Springer
- Date Published:
- Journal Name:
- Immunogenetics
- Volume:
- 75
- Issue:
- 6
- ISSN:
- 0093-7711
- Page Range / eLocation ID:
- 507 to 515
- Subject(s) / Keyword(s):
- T cell receptor genes, marsupials, monotremes.
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1007/s00251-023-01320-w
